Cathode ray tube gun assembly



Aug. 17, 1965 J. vv. SNYDER 3,2%537 CATH'ODE RAY TUBE GUN ASSEMBLY Filedoct. 24, 1961 INVENTOR. F7 C72 2. Jon/1v W. mo/DER United States PatentO 3,201,637 CTHDE RAY TUBE GUN ASSEMBLY .lohn William Snyder, Hatfield,Pa., assigner, by mesne assignments, to ihiico Cerporatien,Philadelphia, Pa., a corperaticn oi elaware Fiied Set. 24, i963, Ser.No. 147,270 3 Claims. (Cl. 313-256) This invention relates generally tocathode-ray tubes, and more particularly to improvements in cathode raytube gun assemblies. The invention, while applicable in its broaderaspect to cathode ray tubes generally, will be described and illustratedin relation to eonstricted neck tubes, Where it has special utility.

In the assembly of electron guns for cathode ray tubes and the like, ithas been the practice to bind the metal electrode elements by insulatorswhich are viscous at the time of application, but which later solidifyinto rigid insulating members. Attachment, or binding, of the metalparts to the insulating members is facilitated by means of axiallyaligned studs or brackets attached to and extending radially from theaforementioned metal parts. The insulating members have comprisedparallelly disposed glass rods heated to a suitable viscous state andapplied individually to one radially extending axially aligned set lofstuds at a time. in the assembly of electrode elements of gun structurecomprising, for example, a plurality of glass rods, the rods must beheated individually, in succession, in order to complete the assembly.In a high production volume of gun structures in which such electrodeassemblies are utilized, a separate heating and cooling operation inattaching each insulator represents a considerable time factor in theoverall production rate.

Also there has been increased demand for more compact television picturetubes of large iluorescent screen area. ing tube depth have involvedincreasing the electron beam deflection angle and reducing the lengthand diameter of the tube neck within which the electron gun is disposed.As to reduction of the dimensions of the tube neck, difteulties havebeen encountered in that the above described glass rod-supported gunstructure does not lend itself to a reduction in diameter to the extentrequired. The present invention is directed primarily to overcomingthese difficulties.

It is therefore a general objective of the invention to provide a novelelectron gun structure permitting reduction in the dimensions of theneck of a cathode ray tube through a unique arrangement of insulatingand support structure. This objective the invention has in common withthe invention described and claimed in the copending application ofSamuel H. Borrnan entitled Cathode Ray Tube Gun Structure, Serial No.146,952, iiled October 23, 1961, and assigned to the assignee of thepresent invention.

It is a further general objective of the invention to provide both amethod of and means for effecting highly accurate assembly of theelements of electron gun structure in a minimum of space.

It is also an objective of the invention to provide a simpliiied andimproved assembly of axially aligned tubular metallic parts, such forexample as electrode elements of a cathode ray tube gan structure of thetype disclosed in the eopending Borrnan application, and further toprovide a rapid, economical, and a highly accurate assembly of the partsin the desired rigid predetermined alignment and in the necessaryinuslated spaced relation.

The invention is featured by the provision of an electron gun which isvery simple yet very rigid in construction. It is an additional featureof the invention that Efforts toward achieveing compactness by reduc`32mb?? Patented Aug. l?, i965 Cce it eliminates the aforementionedheating and cooling of insulating support members which heretofore hadoften resulted in distortion and misalignrnent of the elements of thegun structure, constituting a major problem.

In accordance with the foregoing and other objectives, the invention ischaracterized by provision of a hollow ceramic cylinder in which themetal parts of the gun structure are disposed. The ceramic cylinderincludes means defining transversely extending apertures correspondingto locations lof points of fixation of the gun parts thereto. Accordingto the invention, irregularly shaped metal elements, such for example asstuds, extend through the apertures and are spot Welded in place to themetal gun parts. Each stud is so constructed and arranged as to form athree point Contact between the gun part and an aperture in the ceramiccylinder. When two or more portions of each metal gun part are securedby this method a permanent accurate alignment thereof is achieved byutilizing an annular space of but ls inch thickness or less.

in further accordance with the invention, the irregu larly shaped metalstuds are formed by slicing a metal rod at an angle with respect to aplane perpendicular to the axis of the rod. This angle of cut insuresthat when V a stud extends through an aperture, it engages the metallicgun part at one point for connection thereto and frictionally engagesthe ceramic cylinder Wall at two points, thereby forming a three pointsupporting contact.

It is a feature of the invention, by way of comparison, that Whereaselectron gun structure heretofore held together by glass rods required all/s inch diameter glass tube neck, the present invention permits use ofa glass tube neck of but Sli inch in diameter.

The reduction in diameter afforded by .the invention is invaluable 'whenit is Iconsidered that it -meets the requirement that the turn-s of thecoils forming lthe deflection yoke Ashould be so disposed andconttigured as to be in close proximity to the electrons of the scanningbeam. This arrangement ensures production of the highest possiblemagnetic iield intensi-ty and hence the application of a maximumdeiiecting force to the ,beam electrons emitted from the gun structure.in other Word-s the invention enhances operation of the cathode-ray tubebecause the deiiection yoke is able to operate with maximum eiicien-cy.

The foregoing as Well as other objects and advantages of the inventionlwill .best be understood upon consideration of the Lfollowingdescription Ktaken in light of the accompanying drawing, in which:

FIGURE l is an elevational showing, partly in section and with partsbroken away, of a cathode ray tube ernbodying gun structure made inaccordance with the invention;

FIGURE 2 is a somewhat enlarged `fragmentary showing, partly in section,of ,the gun structure shown in FIG- URE 1 and illustrating alsotechniques util-ized in assembling same and characteristic of theinvention in its method aspect; and

lFIGURES 3 and 4 illustrate additional techniques of gun stuctureassembly which also characterize the invention in its method aspect.

With more particular reference to the drawing, and iirst to FIGURE 1thereof, cathode ray tube 16 is provided -With a generally cylindricalneck portion 151 having .a iiat end 4portion 112 through whichelectrically conductive terminal pins 13 extend.

Gun structure lllt made according to the invention is disposed withinneck porti-on 1li and is supported from the left and right hand pins .13as shown in FIGURE 1. Gun structure 14- cornprises a cathode heater :15disposed Within Aan indirectly heated cathode sleeve fl iover the end ofwhich is disposed electron emissive material Sleeve \`16 is spacedrelative to and supported within generally cylindrical control grid 2dby a suitable insulative disk .17 and a resilient `washer 18 thatfrictiona'lly engage the grid 2'1. The spacing of sleeve 16 is such thatemissive material 20 is disposed adjacent a .small opening 2%2 providedin a flat wall portion of the grid 21.

Grid 21 is supported from pins 13, and as indicated tially .enclose-scontrol grid 21. Sleeve 23 is supported by grid 21 through the agency ofbracket means which compri-ses .s-tud'elements 24 that are aixed .togrid 2l* and extend into apertures .25, the latter extending through`sleeve 23 generally transverse the .axis thereof. The stud elements .24are inclined with respect to and yfrictionally engage the walls ofapertures 2S in the manner best seen in FIGURE 2 which illustrates thepresent inventive mode of frictional engagement of stud elements 24 withthe ceramic sleeve.

In FIGURE l, and in further accordance with constru'ctional features ofgun structure A14, ygenerally cylindrical apertured screen grid 26 and athird grid 350 are Supported in spaced relation las respects one anotherand concentrically with sleeve :23. Finally, the `anode 3d is supiportedin like manner by additional stud elements 24 of .the bracket means,which anode 31 comprises a cornbined getter ring 312 and -snubber means33 disposed in electrical contact with .an electrically conductivecoating (not shown) that extends over interior surface portions 34 oftube 10. Electrical connections of the above described components -aremade tothe pin means 13 and to the conductive coat-ing through means 33by ribbon-like lead wires 37.

Additional important features of .the invention will now be describedwith particular reference to FIGURES 2, 3, and 4. yIrregularly shaped,.prism-like bits of metal comprise stud element-s 24 of the bracketmeans and are form-ed by slicing a cylindrical metal rod 24a (FIGURE 3)at an angle with respect to a plane perpendicular to .the .axis of therod. An angular cut of 20 has been found satisfactory, Iwhich cutinsures that when the stud element 24 is inserted into an upwardlypresented aperture .215 (FIGURE 2) it will be so inclined therein as toengage the underlying grid .at one point and the ceramic sleeve 23 attwo points in .a frictional, wedge-likemanner.

The invention will be still more clearly understood from .a descriptionof the inode of assembly, in which connection it is seen in FIGURE 4that the apertured cylinder 2B is clamped by set screw 36 in a .fixture35 having a mandrel .portion 4t? disposed ttor axial alignment with thecylinder. The Vdiameter of portion 40 corresponds to the inside-diameters of the cylindrical element-s 26, 3l) .and 311 ywhich havebeen positioned thereon in the desired spaced relation as respects oneanother and cylinder 23. `Additional alignment of grid'element 26 isprovided by a central pin-like projection 41 of mandrel' portion 40,said projection extending through the aper- -ture in the element 26. I

With the component elements assembled according to the showing of FIGURE4, and with the .apertures 25 preferably presented upwardly, studelements 24 are inserted into `apertures 25 as best seen in the enlargedshowing afforded by FIGURE 2. With reference to VFIG- URE 2 it wi-ll befurther appreciated that the stud elements also provide means forelectrically connecting a lead wire 37 .to a cylindrical gun component.

With stud elements 24 positioned so that they are inclined as sho-wn lin.FIGURE 2, mild pressure is exerted on each such element by means of aresistance welding electrode as seen at 42 and a su-itable currentpassed between the element .24 .and the adjacent grid element 30 to weldthe same together. Thus aixed to .the grid elea close size match withthe stud elements 24..

ment, the stud elements will irictionally engage the walls of theapertures through which they extend whereby the attached gridv elementis accurately supported. Connection of a lead wire 37 to a stud elementis achieved by applying the weldingelectrode to wir-e 37 in the positionshown in FIGURE 2 and again passing a sui-table weld ing current betweenthe wire and the stud element. The fwelding electrode and suitablecircuitry are conventional, and are shown only diagrammatically inFIGURE 2 as comprising ya voltage source L, an energizing switch S,transformer means T, and the lead wire connections re quired to eiectthe welding current ovv. After welding the upwardly presented studelement-s 24, .the iixture 35 is rotated 180 about its axis to presentthe remaining apertures 25 upwardly and the stud insertion and weldingoperation is repeated as described above. understood that t-he inventioncontemplates use of any desired number of supporting stud elements, andis not limited to the number or the precise shape shown.

' It will further be understood that a similar operation is carried outin attaching the control grid 21 to sleeve 23, whereupon nal attachmentof the remaining gun structure elements is made ias shown in FIGURE l.

The invention is featured by its simplicity of construction and ease ofassembly, particularly when considered in light of the fact that theopenings 25 need not provide Moreover, tolerances capable of beingmaintained in fabrication of ceramic elements of this type are notconducive to providing a uniform close size match, and this problem isreadily overcome by the invention.

While but a single embodiment of the invention has been described, itwill be understood that the invention is susceptible to modication, asis contemplated by the scope of the appended claims. Y

- IV claim: Y

1. In electron gun structure: a tubular electrode; a tubular member ofelectrically non-conductive material enclosing said electrode and havinga common axis therewith; means defining a plurality ofaperturesextending transversely'through said tubular member; and electrodesupporting bracket means aixed to said tubular electrode, said bracketmeans comprising a plurality of rod elements each extending into anassociated one ofV said apertures and each inclined as respects themajor axis of its associated aperture and having portions ofsubstantially lesser cross sectional area than said apertures, lan endportion of each said inclined rod element being aixed t0 said electrodeand oppositely disposed axially spaced lateralportions thereof disposedin frictional electrode supporting engagement with walls of saidapertures.

2. Gun structure according tov claim 1 characterized in that saidtubular member is of a ceramic material.

3. In electron gun structure: tubular electrode means; an elongatedelectrically non-conductive member disposed adjacent said electrodemeans and having apertures extending transversely thereof and throughsaid non-conductive member; and electrode supporting bracket meanscomprising rod-like elements each of substantially less cross-sectionaltarea than and extending into an associated one of said apertures, eachsaid element having a pair of oppositely disposed parallel face portionsinclined as respects t-he major axis of said element, the constructionand arrangement being such that engagement of a recited angular faceportion with said electrode Veiiects inclined positioning of each saidrodlike element within an aperture, as respects the major axis thereof,whereby an element engages opposite, axially spaced sides of anassociated aperture frictionally to retain the electrode means in therecited supported relation.

4. In electron gunv structure: tubular electrode means; elongatedelectrically non-conductive insulative means disposed adjacent saidelectrode means and having apertures extending therethrough transverselyof said tubular electrode means; and electrode supporting bracketscomprising irregularly shaped pieces of metal Welded to said electrodemeans and having portions frictionally engaging both the edge and anopposite portion of the inside surfaces of the material defining saidapertures.

5. In electron gun structure: electrode means; electricallynon-conductive insulative means disposed adjacent said electrode meansand having apertures extending therethrough transversely of saidelectrode means; and electrode supporting brackets comprisingirregularly shaped pieces of metal welded to said electrode means andhaving portions frictionally engaging both the edge and an oppositeportion of the inside surfaces of the material defining said apertures.

6. In electron gun structure: means defining a tubular electrode; atubular member of electrically non-conductive material enclosing saidelectrode and having a common axis therewith; means defining a pluralityof apertures extending transversely of and through said tubular member;and electode supporting bracket means aixed to said tubular electrode,said bracket means comprising a plurality of rod-like elements eachextending into one of said apertures and having a pair of oppostelydisposed parallel face portions positioned with angularity as respectsits axis, the construction and arrangement being such that supportingengagement of a recited angular face portion with said electrode elfectsinclined positioning of each said rod-like element within an aperturewhereby such an element engages opposed, axially spaced sides of theaperture to retain the electrode means in the recited supportedrelation.

7. Gun structure according to claim 6 and further characterized in thateach said rod element comprises a cylindrical section and said faceportions comprise generally elliptical surfaces.

8. In electron gun structure: electrode means; electrically insulativemeans disposed adjacent said electrode means and having aperturesextending therethrough transversely of said electrode means; andelectrode means supporting brackets comprising rod-like elements each ofsubstantially less cross-sectional area than an associated aperture andextending into the associated one of said apertures, said elements eachhaving at least a transverse face portion positioned with angularity asrespects the axis of the element, the construction and arrangement beingsuch that supporting engagement of a recited angular face portion withsaid electrode means eiects inclined positioning of lthe rod-likeelement Within the associated one of said apertures, as respects themajor axis thereof whereby the element engages sides of the associatedaperture frictionally to retain the electrode means in the recitedsupported relation.

References Cited by the Examiner UNITED STATES PATENTS 2,372,649 4/45Binneweg 313-244 X DAVID J. GALVIN, Primary Examiner. RALPH P. NILSON,Examiner.

1. IN ELECTRON GUN STRUCTURE: A TUBULAR ELECTRODE; A TUBULAR MEMBER OFELECTRICALLY NON-CONDUCTIVE MATERIAL ENCLOSING SAID ELECTRODE AND HAVINGA COMMON AXIS THEREWITH; MEANS DEFINING A PLURALITY OF APERTURESEXTENDING TRANSVERSELY THROUGH SAID TUBULAR MEMBER; AND ELECTRODESUPPORTING BRACKET MEANS AFFIXED TO SAID TUBULAR ELECTRODE, SAID BRACKETMEANS COMPRISING A PLURALITY OF ROD ELEMENTS EACH EXTENDING INTO ANASSOCIATED ONE OF SAID APERTURES AND EACH INCLINED AS RESPECTS THE MAJORAXIS OF ITS ASSOCIATED APERTURE AND HAVING PORTIONS OF SUBSTANTIALLYLESSER CROSS SECTIONAL AREA THAN SAID APERTURE, AN END PORTION OF EACHSAID INCLINED ROD ELEMENT BEING AFFIXED TO SAID ELECTRODE AND OPPOSITELYDISPOSED AXIALLY SPACED LATERAL PORTIONS THEREOF DISPOSED IN FRICTIONALELECTRODE SUPPORTING ENGAGEMENT WITH WALLS OF SAID APERTURES.